11 21 500 Replacing crankshaft (M52 / S52 / M52TU / M54 / M56)

(Engine removed.)

Necessary Preliminary Tasks: 

• Removing cylinder head.
• Removing lower timing case cover.
• Removing all pistons, refer to 11 25 530 REMOVING AND INSTALLING OR REPLACING ALL PISTONS (M52 / S52 / M52TU / M54 / M56) .
• Remove end cover at rear; this operation is described in 11 14 151 REPLACING CRANKSHAFT RADIAL SEAL (TRANSMISSION SIDE) .

Checking axial clearance:

If permitted end float is exceeded, check crankshaft, guide bearing shells and engine block, replacing if necessary, end float.

Fig 1: Checking Axial Clearance

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Unfasten screw connection on reinforcement plates.

Fig 2: Removing Reinforcement Plate Retaining Screws

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Unfasten screw connection on main bearing.

Remove main bearing caps (1 to 7).

Lever out crankshaft.

Fig 3: Removing Main Bearing Caps

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If necessary, release incremental gear.

Installation: 

Replace screws.

Install screws and tighten down in two passes.

Tightening torque, refer to 11 21 1AZ in ENGINE - TIGHTENING TORQUES .

Important! 

Check grinding stage of crankshaft, refer to ENGINE - TECHNICAL DATA .

Fig 4: Checking Crankshaft

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Replace main crankshaft bearing shells, refer to 11 21 531 REPLACING ALL MAIN CRANKSHAFT BEARING SHELLS (M52 / S52 / M52TU / M54 / M56) .

Replace conrod bearing shells, refer to 11 24 571 REPLACING ALL CONNECTING ROD BEARINGS (M52 / S52 / M52TU / M54 / M56) .

Replace grooved ball bearings in crankshaft, refer to 11 21 571 REPLACING GROOVED BALL BEARING IN CRANKSHAFT (M52 / S52 / M52TU / M54 / S50 / S54) .